Packaging for optical transceiver module

ABSTRACT

A packaging method of the optical transceiver module for transmitting optical signals is disclosed. The invention includes a base, a case, a transmission unit and a receiving unit. The transmission unit and the receiving unit contain a circuit board, respectively. The base provides two fixing positions for the installation of the two circuit boards. The two circuit boards are installed horizontally and vertically, respectively. This design increases the utilization of the inner space, providing ideal shielding for the elements and circuit boards. A central beam is used to fix the structure and case in a drawable way like a matchbox. This reduces covered area of the circuit board, making the elements easy to be tested and assembled.

BACKGROUND OF THE INVENTION

1. Field of Invention

The invention relates to an optical transceiver packaging for receivingand transmitting optical signal. More particularly, the inventionpertains to an optical transceiver packaging convenient formanufacturing and assembly.

2. Related Art

The optical transceiver module is installed in an electronic device toemit or receive optical signals through optic fibers. Basically, theoptical transceiver module has a case 11, a base 12, a receiver opticalsubassembly (ROSA) 13, a transmitter optical subassembly (TOSA) 14, anda circuit board 15. With reference to FIG. 1, the base 12 supports thecircuit board 15, and the case 11 covers the base 12. The circuit board15 has the functions of transmitting/receiving electrical signal to/fromTOSA/ROSA. The circuit board 15 is connected to the electronic devicethrough its pins 151 so that the electronic device can transmit andreceive optical signals via its transceiving terminal.

The circuit board 15 is parallel to the base 12, with the emitter 14 andthe receiver 13 installed on its front end for connecting with opticfibers. Since the circuit board 15 has both functions of transmissionand reception, it is likely to have crosstalks, deteriorating the signalquality. Any error occurred to the circuit cannot be easily attributedto the reception or transmission. Furthermore, the elements on thecircuit board 15 are limited by the size of the circuit board 15 to beplaced fairly close to one another, resulting in serious crosstalk.

To solve the problem of crosstalks, the prior art has the functions oftransmission and reception separately on two independent circuit boards.As shown in FIG. 2, the two circuit boards 16, 17 have the functions oftransmitting and receiving optical signals and connect to thetransmitter 14 and the receiver 13, respectively. This can reduce theproblem of crosstalks. Moreover, once any error occurs to the system,one can easily identify where the problem is. However, since the twocircuits 16, 17 are installed in parallel, an extra shielding design isneeded to completely solve the crosstalk problem. As the whole opticaltransceiver module is small and the two circuit boards 16, 17 areshielded from each other, the circuit board assembly and its elementtesting and debugging are limited by the span of the two circuit boards.

SUMMARY OF THE INVENTION

The invention provides a packaging method for the optical transceivermodule. It can solve the problems of EMI and crosstalks. The inventionalso efficiently utilizes the inner space of the module to achieve thegoals of easy assembly, tests and manufacturing.

The disclosed packaging method for the optical transceiver moduleincludes a base, a transmission unit, a receiving unit, and a case. Thereceiving unit and the transmission unit contain a circuit board,respectively. The base has two fixing positions for the installation ofthe two circuit boards. The two circuit boards are installedperpendicularly, with one parallel to the base while the otherperpendicular. This design greatly reduces the problems of crosstalksand EMI. On the other hand, the base uses the design of a central beam,so that most of the circuit boards is exposed for convenient assemblyand debugging. The base and the case are combined in a drawable way justlike a matchbox. Therefore, invention can be easily assembled anddifficult to be taken apart.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will become more fully understood from the detaileddescription given hereinbelow illustration only, and thus are notlimitative of the present invention, and wherein:

FIG. 1 is a schematic view of a packaging of an optical transceivermodule in the prior art;

FIG. 2 is a schematic view of another packaging of an opticaltransceiver module in the prior art;

FIG. 3 is an explosive view of the invention;

FIG. 4 is a schematic view of the central beam according to theinvention;

FIGS. 5A and 5B are two assembly views of the case; and

FIG. 6 compares the eye diagrams of the invention and the prior art.

DETAILED DESCRIPTION OF THE INVENTION

According to the optical transceiver packaging method disclosed herein,it includes a base 21, a transmission unit 22, a receiving unit 23, anda case 24 (see FIG. 3). The transmission unit 22 contains a transmissioncircuit board 221 and a laser module 222 connected to its front end. Thetransmission circuit board 221 has pins 223 and several electronicelements 224 so that the transmission unit 22 is able to send outoptical signals. Analogously, the receiving unit 23 contains a receivingcircuit board 231 and a receptacle 232 and a detector 233 both connectedto its front end. The receiving circuit board 231 also has pins 234 andseveral electronic elements 235 so that the receiving unit 23 is able toreceive optical signals.

The base 21 provides two fixing positions 211, 212 for the transmissionunit 22 and the receiving unit 23, respectively. One of them isinstalled horizontally and the other vertically (FIG. 5A). In otherwords, the transmission circuit board 221 and the receiving circuitboard 231 are perpendicular to each other. This reduces the crosstalksproduced between the transmission unit 22 and the receiving unit 23 toits minimum. Owing to such a horizontal-vertical configuration, theinternal space can be utilized with more flexibility and efficiently.Although not shown in the drawing, electric properties of the circuit orthe metal shielding design thus become flexible. Moreover, the base 21uses the design of a central beam. That is, a solid beam is providedonly at the two fixing positions 211, 212. Such a design exposes mostareas on the transmission circuit board 221 and the receiving circuitboard 231 of the transmission unit 22 and the receiving unit 23,respectively. The connecting points or electronic elements thereon arethus not shielded. As shown in FIG. 4, the receiving circuit board 231is vertical with no shielding on its left and right sides, while thetransmission circuit board 221 is horizontal with no shielding above orbeneath it. This is particularly convenient in assembly and testing inthe manufacturing process.

The central beam design in the base 21 does not cover the solderingpoints and the elements at those points on the transmission circuitboard 221 and the receiving circuit board 231. Therefore, it does notrequire additional text fixture. One only needs to directly place thetransmission circuit board 221 and the receiving circuit board 231 onthe fixing positions 211, 212 on the base 21, followed by soldering andsolder the leads of TOSA and ROSA to circuit board. The front end of thebase 21 is provided with connector sockets 213 for plugging the frontends of the transmission unit 22 and the receiving unit 23, for guidingoptic fiber connectors (not shown).

To meet the electromagnetic compatibility requirements, the case 24 canbe made of metal. To minimize the number of elements and to facilitateassembly, the case 24 can be designed like a matchbox. Both front andrear ends of the case 24 are open so that the base 21 can be installedin and contained inside the case 24. The inner side of its lower surfaceis formed with one sliding track 241, corresponding to a sliding groove214 at the bottom of the base 21, so that the base 21 can be easilyinstalled and fixed into the case 24 (see FIG. 4 and 5A). The innersurface opposite to the sliding track 241 is a fixing part 242. Afterthe base 21 is completely installed into the case 24, the fixing part242 moves into a fixing hole 215 on the base 21 and holds the case 24 atthis position, as shown in FIG. SB.

Please refer to FIG. 6 for the crosstalk effects in the invention andthe prior art. “OES” (the abbreviation for Opto electric and systemsLaboratories in Industrial and Technology Research Institute) in thetable refers to the invention. One can easily see the improvement onreducing the crosstalk.

Effects of the Invention

The invention discloses the assembly of an optical transceiver module.The transmission and receiving parts are designed as two independentcircuit boards, installed perpendicular to each other on a base. Such aconfiguration can greatly reduce crosstalks and EMI. The base adopts thecentral beam design to expose most of the area on the circuit boards.This is particularly convenient for testing, adjusting and assembly. Thecase and the base are designed to match with each other so that theassembly is easy.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

What is claimed is:
 1. A packaging for an optical transceiver module foran electronic device to receive and transmit optical signals, whichcomprises: a base defining two fixing positions for installation of theelectronic device; a transmission unit emitting optical signals from theelectronic device and contains a transmission circuit board with aplurality of pins, the transmission circuit board being installed at oneof the fixing positions on the base and having electrical communicationswith the electronic device via its pins; and a receiving unit receivingexternal optical signals to the electronic device and contains areceiving circuit board with a plurality of pins, the receiving circuitboard being installed at the other the fixing position on the baseperpendicular to the transmission circuit board and having electricalcommunications with the electronic device via its pins.
 2. The packagingof claim 1, further comprising a case covering the base to reduce EMI(Electromagnetic Interference) from the receiving circuit board and thetransmission circuit board.
 3. The packaging of claim 2, wherein thecase has a sliding track and the base has a sliding groove, the slidingtrack and sliding groove being designed to match each other so that thebase is combined with the case by sliding into it.
 4. The packaging ofclaim 3, wherein the case has a fixing part and the base has acorresponding fixing hole, the combination of which fixes the relativeposition of the case and the base.
 5. The packaging of claim 4, whereinthe fixing part is on the opposite side to that of the sliding track. 6.The packaging of claim 2, wherein the case has a pair of openings forthe pins of the transmission unit and the receiving unit to stick out ofthe case and to form electrical connection with the electronic device.7. The packaging of claim 1, wherein the two fixing positions on thebase are used to install one of the transmission circuit board and thereceiving circuit board perpendicular to the base while the otherparallel to the base.
 8. The packaging of claim 7, wherein the base usesa central beam design so that most of the area on the transmissioncircuit board and the receiving circuit bard is exposed to thesurrounding environment.
 9. The packaging of claim 1, wherein the basecontains a metal shielding unit.
 10. A packaging for an opticaltransceiver module for an electronic device to receive and transmitoptical signals, which comprises: a base defining two fixing positionsfor installation of the electronic device; a transmission unit emittingoptical signals from the electronic device and contains a transmissioncircuit board with a plurality of pins, the transmission circuit boardbeing installed at one of the fixing positions on the base and havingelectrical communications with the electronic device via its pins; and areceiving unit receiving external optical signals to the electronicdevice and contains a receiving circuit board with a plurality of pins,the receiving circuit board being installed at the other the fixingposition on the base perpendicular to the transmission circuit board andhaving electrical communications with the electronic device via itspins; and wherein the base uses a central beam design so that most ofthe area on the transmission circuit board and the receiving circuitboard is exposed to the surrounding environment.